Apparatus for heat treatment of fine material

ABSTRACT

The apparatus comprises preheating, firing and cooling apparatus. Hot gases and fine material are passed concurrently through a firing chamber, and a separator is directly connected to the firing chamber.

Inventor App]v No. Filed Patented Assignee Priority Horst Ritzmnnn Neubockum, Germany 864.762

Oct. 8, 1969 Sept. 7, 11971 lPolysius AG Neuheclrum, Germany Nov. 6, 196% Germany APPARATUS FOR HEAT TREATMENT (NF lFllNlE MATERIAL 3 Claims, 1 Drawing Fig.

[51] llnt. C1 1 27b 15/00 [50] ll ielnl 01 Search 263/21 1 References Cikedl UNITED STATES PATENTS 3,410,542 11/1968 Mazurov et a1. 263/21 Primary Examiner-Charles J. Myhre Attorney-Marshall 8; Yeasting ABSTRAC'llrThe apparatus comprises preheating, firing and cooling apparatus. Hot gases and fine material are passes concurrently through a firing chamber, and a separator is directly 263/211R connectedtothefiringchamber.

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5111 g I y 5 1 m EU in l I 3W a f r7 1 y M .&':;, I f l IL I, w M l APPARATUS FOR HEAT TREATMENT OF T llNE MATERIAL BACKGROUND OF THE INVENTION The invention relates to an apparatus for heat treatment of finely divided material, particularly raw..material for the manufacture of cement, including a preheating apparatus, a firing apparatus and a cooling apparatus.

Apparatus is known in which a rotary kiln is provided as the firing apparatus. This apparatus, with moving parts, has disadvantages in that it is subject to substantial wear, requires extensive maintenance in order to prevent breakdowns and entails great initial cost as well as very considerable space requirements.

Other installations are known which in general consist of a vertical shaft through which the material travels downward and the gas travels upward. In the middle part of the shaft there is provided a firing zone furnished with a burner, from which the upward-flowing products of combustion heat the material, while the fired material in the lower part of the shaft is cooled by the upward-flowing secondary air. Since in installations of this type the material must travel in countercurrent to the gases in a downward direction, in the case of powdery or finely divided material it is impossible to use high gas velocities and accordingly impossible to attain high output capacities.

SUMMARY OF THE INVENTION Accordingly, the object of the invention is to construct an apparatus of the class which has been described in such a manner that the firing apparatus, having no moving parts, on the one hand is relatively inexpensive to construct, and on the other hand permits the attainment of high output capacities.

This object is attained, in accordance with the invention, in that the firing apparatus is constructed in the form of a firing chamber which is fixed and through which the fine material and the hot gases flow in the same direction, and to which a separator is directly connected.

Since the firing chamber of the apparatus according to the invention is fixed, the abrasion and breakdowns due to moving parts are eliminated. The cost of construction and thus the cost of installation are substantially reduced in comparison to the known apparatus hereinbefore described. The concurrent flow of material and hot gases in the firing chamber makes possible the use of high rates of flow and thus the attainment of great output capacities.

In accordance with an advantageous embodiment of the invention, at least one cooling air supply passage discharges into the end of the firing chamber adjacent to the separator, and the separator and/or the firing chamber are provided with a porous inner wall for the introduction of cooling air. These arrangements assure that the hot fine material which has been fired will be partly cooled whereby formation of deposits on the inner wall of the separator will be safely prevented. Introduction of cooling air into the firing chamber protects against formation of deposits in the location where such pro tection is particularly needed. The cooling air introduced into the firing chamber can form at the same time a part of the air required for combustion.

BRIEF DESCRIPTION OF THE DRAWING The drawing is a schematic view of an apparatus embodying the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT The illustrated apparatus comprises in general a two-stage preheater 1, a generally horizontal firing apparatus 2 arranged thereunder, and a similar two-stage cooler 3, which is connected to the firing apparatus. The preheater l is composed of two cyclone separators 4 and 5, arranged oneabove the other, wherein the discharge duct 6 of the cyclone separator is connected to the inlet of the cyclone separator 4, and the tailings outlet 7 of the cyclone separator A is connected to the gas supply duct 8 of the cyclone separator 5. The tailings outlet 10 of the cyclone separator 5 is connected by a passage 9 to a mixing chamber 12, which is located ahead of a tube-shaped firing chamber lll. Also projecting into this mixing chamber is the end of a primary air supply duct M, which is formed as an injection nozzle T3. The mixing chamber 12 and also a burner nozzle 116 connected with a' gas supply pipe discharge into the rear end of the firing chamber llll. In the vicinity of its other end, the firing chamber 111 is surrounded by an annular duct 17,,from which several branch ducts 17 lead into the firing chamber. Directly connected to this end of the firing chamber llll is a cyclone separator 18, whose central discharge pipe is connected with the gas supply pipe 8 of the cyclone separator 5. The material outlet 19 of this cyclone separator is connected by means of a passage 20 to a duct 2ll which connects the inlet of the cyclone separator 22 with the central discharge pipe of a cyclone separator 23 which with the separator 22 constitutes a cooler 3. The central discharge pipe of the cyclone separator 22 discharges into the primary air supply duct M. The material discharge pipe 26 leading from the tailings outlet 25 of the cyclone separator 22 discharges into the air duct 24l which leads into the cyclone separator 23.

The operation of the apparatus is as follows: fresh air (arrow 27) enters the apparatus through the duct 24 as cooling air, and travels through the cyclone separator 23, the duct 21, the cyclone separator 22 and the primary air supply duct M to the firing apparatus 2, as primary air (28) which has been pre' heated in the cooler 3. The injector nozzle 13 blows the primary air into the mixing chamber 12. From there it travels into the firing chamber 111 and serves for combustion of the fuel introduced through the burner nozzle 16, for example gas (arrow 29). The hot gases (arrow 30) then flow to the cyclone separator l8. From this cyclone separator the hot gases (arrow 30) flow through the gas supply duct 8 to the lower cyclone separator 5 of the preheater I. It travels through the duct 6 and the cyclone separator 4 and is finally (if desired after dust removal) discharged into the atmosphere.

Fine material (arrow 31) is introduced into the gas supply pipe t3 in the zone preceding the inlet of the upper cyclone separator A of the preheater ll. It travels with the hot gases (arrow 30) into the cyclone separator 4, is there separated, and then travels through the outlet 7 into the duct 3. The hot gases flowing therein.(arrow 34)) carry the fine material (arrow 3i) into the lower cyclone separator 5 of the preheater. The fine material which in this manner has been preheated and if desired simultaneously partially deacidified flows through the outlet l0 and the fine material supply pipe 3 into the mixing chamber T2 of the firing apparatus 2. The primary air (arrow 23) injected into the mixing chamber through the injection nozzle 13 carries the fine material (arrow 31) into the firing chamber ill, where it is fired in the flame from the burner nozzle T6. The fine material is held in suspension by the hot gases (arrow 30) and travels concurrently therewith into the directly connected cyclone separator 11%. Before being discharged. from the firing chamber II, the fine material is subjected to the action of cooling air (arrow 32) which is injected from the annular duct 117 and its branch ducts ll7 into the periphery of the firing chamber. The purpose of this arrangement is a partial cooling of the fully fired fine material, in order to prevent the formation of a deposit on the interior of the cyclone separator lift.

The fine material (arrow 31) separated in the cyclone separator llti travels through the outlet l9 and the passage 2t) to the cooler 3. The cooling air flowing into the duct 21 carries the fine material into the cyclone separator 22. In the latter it is separated and travels through the outlet 25 and the passage 26, as well as through the duct 24 with the fresh air (arrow 27) into the lower cyclone separator 23 of the cooler 3. Here it is removed as final product 33.

As it will be evident from the description of the embodiment, the details of the multistage preheater ll and of the cause them to mix and then flow axially into the tubular firing chamber through the axial inlet, and a separating chamber, for precipitating the fired fine material, which is directly connected to the other end of the tubular firing chamber.

2. Apparatus according to claim 1, wherein at least one cooling air supply passage discharges into the end of the firing chamber adjacent to the separating chamber.

3. Apparatus according to claim 1, wherein the firing chamber is substantially horizontal. 

1. Apparatus for heat treatment of fine material, comprising an air preheater and a fine material preheater, wherein the improvement comprises a tubular firing chamber having an axial inlet at one end which connects the firing chamber to a premixing chamber, means for introducing the preheated fine material and preheated air into the premixing chamber, to cause them to mix and then flow axially into the tubular firing chamber through the axial inlet, and a separating chamber, for precipitating the fired fine material, which is directly connected to the other end of the tubular firing chamber.
 2. Apparatus according to claim 1, wherein at least one cooling air supply passage discharges into the end of the firing chamber adjacent to the separating chamber.
 3. Apparatus according to claim 1, wherein the firing chamber is substantially horizontal. 